Add more filter priority levels

src/core/ext/filters/client_channel/client_channel_plugin.cc

@@ -56,7 +56,7 @@ void grpc_client_channel_init(void) {
   grpc_register_http_proxy_mapper();
   grpc_subchannel_index_init();
   grpc_channel_init_register_stage(
-      GRPC_CLIENT_CHANNEL, GRPC_CHANNEL_INIT_BUILTIN_PRIORITY, append_filter,
+      GRPC_CLIENT_CHANNEL, GRPC_CHANNEL_INIT_PRIORITY_MAX, append_filter,
       (void*)&grpc_client_channel_filter);
   grpc_http_connect_register_handshaker_factory();
 }

src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc

@@ -1880,7 +1880,7 @@ void grpc_lb_policy_grpclb_init() {
           grpc_core::UniquePtr<grpc_core::LoadBalancingPolicyFactory>(
               grpc_core::New<grpc_core::GrpcLbFactory>()));
   grpc_channel_init_register_stage(GRPC_CLIENT_SUBCHANNEL,
-                                   GRPC_CHANNEL_INIT_BUILTIN_PRIORITY,
+                                   GRPC_CHANNEL_INIT_PRIORITY_LOW,
                                    maybe_add_client_load_reporting_filter,
                                    (void*)&grpc_client_load_reporting_filter);
 }

src/core/ext/filters/deadline/deadline_filter.cc

@@ -379,10 +379,10 @@ static bool maybe_add_deadline_filter(grpc_channel_stack_builder* builder,
 
 void grpc_deadline_filter_init(void) {
   grpc_channel_init_register_stage(
-      GRPC_CLIENT_DIRECT_CHANNEL, GRPC_CHANNEL_INIT_BUILTIN_PRIORITY,
+      GRPC_CLIENT_DIRECT_CHANNEL, GRPC_CHANNEL_INIT_PRIORITY_VERY_HIGH,
       maybe_add_deadline_filter, (void*)&grpc_client_deadline_filter);
   grpc_channel_init_register_stage(
-      GRPC_SERVER_CHANNEL, GRPC_CHANNEL_INIT_BUILTIN_PRIORITY,
+      GRPC_SERVER_CHANNEL, GRPC_CHANNEL_INIT_PRIORITY_VERY_HIGH,
       maybe_add_deadline_filter, (void*)&grpc_server_deadline_filter);
 }
 

src/core/ext/filters/http/client_authority_filter.cc

@@ -146,12 +146,12 @@ static bool add_client_authority_filter(grpc_channel_stack_builder* builder,
 }
 
 void grpc_client_authority_filter_init(void) {
-  grpc_channel_init_register_stage(GRPC_CLIENT_SUBCHANNEL, INT_MAX,
-                                   add_client_authority_filter,
-                                   (void*)&grpc_client_authority_filter);
-  grpc_channel_init_register_stage(GRPC_CLIENT_DIRECT_CHANNEL, INT_MAX,
-                                   add_client_authority_filter,
-                                   (void*)&grpc_client_authority_filter);
+  grpc_channel_init_register_stage(
+      GRPC_CLIENT_SUBCHANNEL, GRPC_CHANNEL_INIT_PRIORITY_HIGH,
+      add_client_authority_filter, (void*)&grpc_client_authority_filter);
+  grpc_channel_init_register_stage(
+      GRPC_CLIENT_DIRECT_CHANNEL, GRPC_CHANNEL_INIT_PRIORITY_HIGH,
+      add_client_authority_filter, (void*)&grpc_client_authority_filter);
 }
 
 void grpc_client_authority_filter_shutdown(void) {}

src/core/ext/filters/http/http_filters_plugin.cc

@@ -18,6 +18,7 @@
 
 #include <grpc/support/port_platform.h>
 
+#include <limits.h>
 #include <string.h>
 
 #include "src/core/ext/filters/http/client/http_client_filter.h"
@@ -51,15 +52,15 @@ static bool maybe_add_optional_filter(grpc_channel_stack_builder* builder,
   bool enable = grpc_channel_arg_get_bool(
       grpc_channel_args_find(channel_args, filtarg->control_channel_arg),
       !grpc_channel_args_want_minimal_stack(channel_args));
-  return enable ? grpc_channel_stack_builder_prepend_filter(
+  return enable ? grpc_channel_stack_builder_append_filter(
                       builder, filtarg->filter, nullptr, nullptr)
                 : true;
 }
 
-static bool maybe_add_required_filter(grpc_channel_stack_builder* builder,
-                                      void* arg) {
+static bool maybe_append_required_filter(grpc_channel_stack_builder* builder,
+                                         void* arg) {
   return is_building_http_like_transport(builder)
-             ? grpc_channel_stack_builder_prepend_filter(
+             ? grpc_channel_stack_builder_append_filter(
                    builder, static_cast<const grpc_channel_filter*>(arg),
                    nullptr, nullptr)
              : true;
@@ -67,23 +68,23 @@ static bool maybe_add_required_filter(grpc_channel_stack_builder* builder,
 
 void grpc_http_filters_init(void) {
   grpc_channel_init_register_stage(GRPC_CLIENT_SUBCHANNEL,
-                                   GRPC_CHANNEL_INIT_BUILTIN_PRIORITY,
+                                   GRPC_CHANNEL_INIT_PRIORITY_HIGH,
                                    maybe_add_optional_filter, &compress_filter);
   grpc_channel_init_register_stage(GRPC_CLIENT_DIRECT_CHANNEL,
-                                   GRPC_CHANNEL_INIT_BUILTIN_PRIORITY,
+                                   GRPC_CHANNEL_INIT_PRIORITY_HIGH,
                                    maybe_add_optional_filter, &compress_filter);
   grpc_channel_init_register_stage(GRPC_SERVER_CHANNEL,
-                                   GRPC_CHANNEL_INIT_BUILTIN_PRIORITY,
+                                   GRPC_CHANNEL_INIT_PRIORITY_HIGH,
                                    maybe_add_optional_filter, &compress_filter);
   grpc_channel_init_register_stage(
-      GRPC_CLIENT_SUBCHANNEL, GRPC_CHANNEL_INIT_BUILTIN_PRIORITY,
-      maybe_add_required_filter, (void*)&grpc_http_client_filter);
+      GRPC_CLIENT_SUBCHANNEL, GRPC_CHANNEL_INIT_PRIORITY_HIGH,
+      maybe_append_required_filter, (void*)&grpc_http_client_filter);
   grpc_channel_init_register_stage(
-      GRPC_CLIENT_DIRECT_CHANNEL, GRPC_CHANNEL_INIT_BUILTIN_PRIORITY,
-      maybe_add_required_filter, (void*)&grpc_http_client_filter);
+      GRPC_CLIENT_DIRECT_CHANNEL, GRPC_CHANNEL_INIT_PRIORITY_HIGH,
+      maybe_append_required_filter, (void*)&grpc_http_client_filter);
   grpc_channel_init_register_stage(
-      GRPC_SERVER_CHANNEL, GRPC_CHANNEL_INIT_BUILTIN_PRIORITY,
-      maybe_add_required_filter, (void*)&grpc_http_server_filter);
+      GRPC_SERVER_CHANNEL, GRPC_CHANNEL_INIT_PRIORITY_HIGH,
+      maybe_append_required_filter, (void*)&grpc_http_server_filter);
 }
 
 void grpc_http_filters_shutdown(void) {}

src/core/ext/filters/load_reporting/server_load_reporting_filter.cc

@@ -345,7 +345,8 @@ struct ServerLoadReportingFilterStaticRegistrar {
     if (registered) return;
     RegisterChannelFilter<ServerLoadReportingChannelData,
                           ServerLoadReportingCallData>(
-        "server_load_reporting", GRPC_SERVER_CHANNEL, INT_MAX,
+        "server_load_reporting", GRPC_SERVER_CHANNEL,
+        GRPC_CHANNEL_INIT_PRIORITY_VERY_LOW, true,
         MaybeAddServerLoadReportingFilter);
     // Access measures to ensure they are initialized. Otherwise, we can't
     // create any valid view before the first RPC.

src/core/ext/filters/max_age/max_age_filter.cc

@@ -536,7 +536,7 @@ static bool maybe_add_max_age_filter(grpc_channel_stack_builder* builder,
 
 void grpc_max_age_filter_init(void) {
   grpc_channel_init_register_stage(GRPC_SERVER_CHANNEL,
-                                   GRPC_CHANNEL_INIT_BUILTIN_PRIORITY,
+                                   GRPC_CHANNEL_INIT_PRIORITY_LOW,
                                    maybe_add_max_age_filter, nullptr);
 }
 

src/core/ext/filters/message_size/message_size_filter.cc

@@ -311,13 +311,13 @@ static bool maybe_add_message_size_filter(grpc_channel_stack_builder* builder,
 
 void grpc_message_size_filter_init(void) {
   grpc_channel_init_register_stage(GRPC_CLIENT_SUBCHANNEL,
-                                   GRPC_CHANNEL_INIT_BUILTIN_PRIORITY,
+                                   GRPC_CHANNEL_INIT_PRIORITY_LOW,
                                    maybe_add_message_size_filter, nullptr);
   grpc_channel_init_register_stage(GRPC_CLIENT_DIRECT_CHANNEL,
-                                   GRPC_CHANNEL_INIT_BUILTIN_PRIORITY,
+                                   GRPC_CHANNEL_INIT_PRIORITY_LOW,
                                    maybe_add_message_size_filter, nullptr);
   grpc_channel_init_register_stage(GRPC_SERVER_CHANNEL,
-                                   GRPC_CHANNEL_INIT_BUILTIN_PRIORITY,
+                                   GRPC_CHANNEL_INIT_PRIORITY_LOW,
                                    maybe_add_message_size_filter, nullptr);
 }
 

src/core/lib/channel/connected_channel.cc

@@ -228,8 +228,8 @@ static void bind_transport(grpc_channel_stack* channel_stack,
       grpc_transport_stream_size(static_cast<grpc_transport*>(t));
 }
 
-bool grpc_add_connected_filter(grpc_channel_stack_builder* builder,
-                               void* arg_must_be_null) {
+bool grpc_append_connected_filter(grpc_channel_stack_builder* builder,
+                                  void* arg_must_be_null) {
   GPR_ASSERT(arg_must_be_null == nullptr);
   grpc_transport* t = grpc_channel_stack_builder_get_transport(builder);
   GPR_ASSERT(t != nullptr);

src/core/lib/channel/connected_channel.h

@@ -25,8 +25,8 @@
 
 extern const grpc_channel_filter grpc_connected_filter;
 
-bool grpc_add_connected_filter(grpc_channel_stack_builder* builder,
-                               void* arg_must_be_null);
+bool grpc_append_connected_filter(grpc_channel_stack_builder* builder,
+                                  void* arg_must_be_null);
 
 /* Debug helper to dig the transport stream out of a call element */
 grpc_stream* grpc_connected_channel_get_stream(grpc_call_element* elem);

src/core/lib/surface/channel_init.h

@@ -19,13 +19,38 @@
 #ifndef GRPC_CORE_LIB_SURFACE_CHANNEL_INIT_H
 #define GRPC_CORE_LIB_SURFACE_CHANNEL_INIT_H
 
+#include <limits.h>
+
 #include <grpc/support/port_platform.h>
 
 #include "src/core/lib/channel/channel_stack_builder.h"
 #include "src/core/lib/surface/channel_stack_type.h"
 #include "src/core/lib/transport/transport.h"
 
-#define GRPC_CHANNEL_INIT_BUILTIN_PRIORITY 10000
+// Priority for channel registration functions to be used in
+// grpc_channel_init_register_stage().  The priority dictates the
+// order in which the registration functions run.
+//
+// When used to register a filter, the filter can either be appended or
+// prepended, thus dictating whether the filter goes at the top or bottom of
+// the stack. Higher priority functions can get closer to the top or bottom
+// of the stack than lower priority functions.
+enum {
+  // Default level. Most of filters should use this level if their location in
+  // the stack does not matter.
+  GRPC_CHANNEL_INIT_PRIORITY_LOW = 0,
+  // For filters that should be added after the group of filters with default
+  // priority, such as auth filters.
+  GRPC_CHANNEL_INIT_PRIORITY_MED = 10000,
+  // For filters that need to be close to top or bottom, such as protocol-level
+  // filters (client_authority, http-client, http-server) and stats (census).
+  GRPC_CHANNEL_INIT_PRIORITY_HIGH = 20000,
+  // For filters that need to be very close to the wire or surface.
+  GRPC_CHANNEL_INIT_PRIORITY_VERY_HIGH = 30000,
+  // For things that have to happen last, such as connected channel filter or
+  // surface server filter. Consider as reserved for gRPC internals.
+  GRPC_CHANNEL_INIT_PRIORITY_MAX = INT_MAX
+};
 
 /// This module provides a way for plugins (and the grpc core library itself)
 /// to register mutators for channel stacks.

src/core/lib/surface/init.cc

@@ -70,11 +70,6 @@ static void do_basic_init(void) {
   g_initializations = 0;
 }
 
-static bool append_filter(grpc_channel_stack_builder* builder, void* arg) {
-  return grpc_channel_stack_builder_append_filter(
-      builder, static_cast<const grpc_channel_filter*>(arg), nullptr, nullptr);
-}
-
 static bool prepend_filter(grpc_channel_stack_builder* builder, void* arg) {
   return grpc_channel_stack_builder_prepend_filter(
       builder, static_cast<const grpc_channel_filter*>(arg), nullptr, nullptr);
@@ -82,19 +77,20 @@ static bool prepend_filter(grpc_channel_stack_builder* builder, void* arg) {
 
 static void register_builtin_channel_init() {
   grpc_channel_init_register_stage(GRPC_CLIENT_SUBCHANNEL,
-                                   GRPC_CHANNEL_INIT_BUILTIN_PRIORITY,
-                                   grpc_add_connected_filter, nullptr);
+                                   GRPC_CHANNEL_INIT_PRIORITY_MAX,
+                                   grpc_append_connected_filter, nullptr);
   grpc_channel_init_register_stage(GRPC_CLIENT_DIRECT_CHANNEL,
-                                   GRPC_CHANNEL_INIT_BUILTIN_PRIORITY,
-                                   grpc_add_connected_filter, nullptr);
+                                   GRPC_CHANNEL_INIT_PRIORITY_MAX,
+                                   grpc_append_connected_filter, nullptr);
   grpc_channel_init_register_stage(GRPC_SERVER_CHANNEL,
-                                   GRPC_CHANNEL_INIT_BUILTIN_PRIORITY,
-                                   grpc_add_connected_filter, nullptr);
+                                   GRPC_CHANNEL_INIT_PRIORITY_MAX,
+                                   grpc_append_connected_filter, nullptr);
   grpc_channel_init_register_stage(GRPC_CLIENT_LAME_CHANNEL,
-                                   GRPC_CHANNEL_INIT_BUILTIN_PRIORITY,
-                                   append_filter, (void*)&grpc_lame_filter);
-  grpc_channel_init_register_stage(GRPC_SERVER_CHANNEL, INT_MAX, prepend_filter,
-                                   (void*)&grpc_server_top_filter);
+                                   GRPC_CHANNEL_INIT_PRIORITY_MAX,
+                                   prepend_filter, (void*)&grpc_lame_filter);
+  grpc_channel_init_register_stage(
+      GRPC_SERVER_CHANNEL, GRPC_CHANNEL_INIT_PRIORITY_MAX, prepend_filter,
+      (void*)&grpc_server_top_filter);
 }
 
 typedef struct grpc_plugin {

src/core/lib/surface/init_secure.cc

@@ -67,14 +67,17 @@ static bool maybe_prepend_server_auth_filter(
 }
 
 void grpc_register_security_filters(void) {
-  // Register the auth client with a priority < INT_MAX to allow the authority
+  // Register the auth client with a low priority to allow the authority
   // filter -on which the auth filter depends- to be higher on the channel
   // stack.
-  grpc_channel_init_register_stage(GRPC_CLIENT_SUBCHANNEL, INT_MAX - 1,
+  grpc_channel_init_register_stage(GRPC_CLIENT_SUBCHANNEL,
+                                   GRPC_CHANNEL_INIT_PRIORITY_MED,
                                    maybe_prepend_client_auth_filter, nullptr);
-  grpc_channel_init_register_stage(GRPC_CLIENT_DIRECT_CHANNEL, INT_MAX - 1,
+  grpc_channel_init_register_stage(GRPC_CLIENT_DIRECT_CHANNEL,
+                                   GRPC_CHANNEL_INIT_PRIORITY_MED,
                                    maybe_prepend_client_auth_filter, nullptr);
-  grpc_channel_init_register_stage(GRPC_SERVER_CHANNEL, INT_MAX,
+  grpc_channel_init_register_stage(GRPC_SERVER_CHANNEL,
+                                   GRPC_CHANNEL_INIT_PRIORITY_MED,
                                    maybe_prepend_server_auth_filter, nullptr);
 }
 

src/cpp/common/channel_filter.cc

@@ -78,8 +78,13 @@ bool MaybeAddFilter(grpc_channel_stack_builder* builder, void* arg) {
         grpc_channel_stack_builder_get_channel_arguments(builder);
     if (!filter.include_filter(*args)) return true;
   }
-  return grpc_channel_stack_builder_prepend_filter(builder, &filter.filter,
-                                                   nullptr, nullptr);
+  if (filter.prepend) {
+    return grpc_channel_stack_builder_prepend_filter(builder, &filter.filter,
+                                                     nullptr, nullptr);
+  } else {
+    return grpc_channel_stack_builder_append_filter(builder, &filter.filter,
+                                                    nullptr, nullptr);
+  }
 }
 
 }  // namespace

src/cpp/common/channel_filter.h

@@ -36,7 +36,8 @@
 /// \c ChannelData. Then register the filter using something like this:
 /// \code{.cpp}
 ///   RegisterChannelFilter<MyChannelDataSubclass, MyCallDataSubclass>(
-///       "name-of-filter", GRPC_SERVER_CHANNEL, INT_MAX, nullptr);
+///       "name-of-filter", GRPC_SERVER_CHANNEL, GRPC_CHANNEL_INIT_PRIORITY_LOW,
+///       true, nullptr);
 /// \endcode
 
 namespace grpc {
@@ -351,6 +352,7 @@ class ChannelFilter final {
 struct FilterRecord {
   grpc_channel_stack_type stack_type;
   int priority;
+  bool prepend;
   std::function<bool(const grpc_channel_args&)> include_filter;
   grpc_channel_filter filter;
 };
@@ -363,12 +365,14 @@ void ChannelFilterPluginShutdown();
 
 /// Registers a new filter.
 /// Must be called by only one thread at a time.
+/// The \a prepend argument decides whether to prepend or append the filter.
 /// The \a include_filter argument specifies a function that will be called
 /// to determine at run-time whether or not to add the filter. If the
 /// value is nullptr, the filter will be added unconditionally.
 template <typename ChannelDataType, typename CallDataType>
 void RegisterChannelFilter(
     const char* name, grpc_channel_stack_type stack_type, int priority,
+    bool prepend,
     std::function<bool(const grpc_channel_args&)> include_filter) {
   // If we haven't been called before, initialize channel_filters and
   // call grpc_register_plugin().
@@ -383,6 +387,7 @@ void RegisterChannelFilter(
   internal::FilterRecord filter_record = {
       stack_type,
       priority,
+      prepend,
       include_filter,
       {FilterType::StartTransportStreamOpBatch, FilterType::StartTransportOp,
        FilterType::call_data_size, FilterType::InitCallElement,

src/cpp/ext/filters/census/grpc_plugin.cc

@@ -32,10 +32,12 @@ namespace grpc {
 
 void RegisterOpenCensusPlugin() {
   RegisterChannelFilter<CensusChannelData, CensusClientCallData>(
-      "opencensus_client", GRPC_CLIENT_CHANNEL, INT_MAX /* priority */,
+      "opencensus_client", GRPC_CLIENT_CHANNEL,
+      GRPC_CHANNEL_INIT_PRIORITY_VERY_HIGH, true /* prepend */,
       nullptr /* condition function */);
   RegisterChannelFilter<CensusChannelData, CensusServerCallData>(
-      "opencensus_server", GRPC_SERVER_CHANNEL, INT_MAX /* priority */,
+      "opencensus_server", GRPC_SERVER_CHANNEL,
+      GRPC_CHANNEL_INIT_PRIORITY_VERY_HIGH, true /* prepend */,
       nullptr /* condition function */);
 
   // Access measures to ensure they are initialized. Otherwise, creating a view

test/core/channel/minimal_stack_is_minimal_test.cc

@@ -85,21 +85,21 @@ int main(int argc, char** argv) {
 
   // tests with a default stack
   errors +=
-      CHECK_STACK("unknown", nullptr, GRPC_CLIENT_DIRECT_CHANNEL, "authority",
-                  "message_size", "deadline", "connected", NULL);
+      CHECK_STACK("unknown", nullptr, GRPC_CLIENT_DIRECT_CHANNEL, "deadline",
+                  "authority", "message_size", "connected", NULL);
   errors += CHECK_STACK("unknown", nullptr, GRPC_CLIENT_SUBCHANNEL, "authority",
                         "message_size", "connected", NULL);
   errors += CHECK_STACK("unknown", nullptr, GRPC_SERVER_CHANNEL, "server",
-                        "message_size", "deadline", "connected", NULL);
+                        "deadline", "message_size", "connected", NULL);
   errors += CHECK_STACK("chttp2", nullptr, GRPC_CLIENT_DIRECT_CHANNEL,
-                        "authority", "message_size", "deadline", "http-client",
-                        "message_compress", "connected", NULL);
+                        "deadline", "authority", "message_size",
+                        "message_compress", "http-client", "connected", NULL);
   errors += CHECK_STACK("chttp2", nullptr, GRPC_CLIENT_SUBCHANNEL, "authority",
-                        "message_size", "http-client", "message_compress",
+                        "message_size", "message_compress", "http-client",
                         "connected", NULL);
   errors += CHECK_STACK("chttp2", nullptr, GRPC_SERVER_CHANNEL, "server",
-                        "message_size", "deadline", "http-server",
-                        "message_compress", "connected", NULL);
+                        "deadline", "message_size", "message_compress",
+                        "http-server", "connected", NULL);
   errors += CHECK_STACK(nullptr, nullptr, GRPC_CLIENT_CHANNEL, "client-channel",
                         NULL);
 

test/core/end2end/tests/filter_call_init_fails.cc

@@ -438,7 +438,6 @@ static bool maybe_add_server_channel_filter(grpc_channel_stack_builder* builder,
     // must be the last one.  So we add it right before the last one.
     grpc_channel_stack_builder_iterator* it =
         grpc_channel_stack_builder_create_iterator_at_last(builder);
-    GPR_ASSERT(grpc_channel_stack_builder_move_prev(it));
     const bool retval = grpc_channel_stack_builder_add_filter_before(
         it, &test_filter, nullptr, nullptr);
     grpc_channel_stack_builder_iterator_destroy(it);
@@ -457,7 +456,6 @@ static bool maybe_add_client_channel_filter(grpc_channel_stack_builder* builder,
     // must be the last one.  So we add it right before the last one.
     grpc_channel_stack_builder_iterator* it =
         grpc_channel_stack_builder_create_iterator_at_last(builder);
-    GPR_ASSERT(grpc_channel_stack_builder_move_prev(it));
     const bool retval = grpc_channel_stack_builder_add_filter_before(
         it, &test_filter, nullptr, nullptr);
     grpc_channel_stack_builder_iterator_destroy(it);
@@ -476,7 +474,6 @@ static bool maybe_add_client_subchannel_filter(
     // must be the last one.  So we add it right before the last one.
     grpc_channel_stack_builder_iterator* it =
         grpc_channel_stack_builder_create_iterator_at_last(builder);
-    GPR_ASSERT(grpc_channel_stack_builder_move_prev(it));
     const bool retval = grpc_channel_stack_builder_add_filter_before(
         it, &test_filter, nullptr, nullptr);
     grpc_channel_stack_builder_iterator_destroy(it);
@@ -487,13 +484,17 @@ static bool maybe_add_client_subchannel_filter(
 }
 
 static void init_plugin(void) {
-  grpc_channel_init_register_stage(GRPC_SERVER_CHANNEL, INT_MAX,
+  grpc_channel_init_register_stage(GRPC_SERVER_CHANNEL,
+                                   GRPC_CHANNEL_INIT_PRIORITY_MAX,
                                    maybe_add_server_channel_filter, nullptr);
-  grpc_channel_init_register_stage(GRPC_CLIENT_CHANNEL, INT_MAX,
+  grpc_channel_init_register_stage(GRPC_CLIENT_CHANNEL,
+                                   GRPC_CHANNEL_INIT_PRIORITY_MAX,
                                    maybe_add_client_channel_filter, nullptr);
-  grpc_channel_init_register_stage(GRPC_CLIENT_SUBCHANNEL, INT_MAX,
+  grpc_channel_init_register_stage(GRPC_CLIENT_SUBCHANNEL,
+                                   GRPC_CHANNEL_INIT_PRIORITY_MAX,
                                    maybe_add_client_subchannel_filter, nullptr);
-  grpc_channel_init_register_stage(GRPC_CLIENT_DIRECT_CHANNEL, INT_MAX,
+  grpc_channel_init_register_stage(GRPC_CLIENT_DIRECT_CHANNEL,
+                                   GRPC_CHANNEL_INIT_PRIORITY_MAX,
                                    maybe_add_client_channel_filter, nullptr);
 }
 

test/core/end2end/tests/filter_latency.cc

@@ -314,7 +314,6 @@ static bool maybe_add_filter(grpc_channel_stack_builder* builder, void* arg) {
     // must be the last one.  So we add it right before the last one.
     grpc_channel_stack_builder_iterator* it =
         grpc_channel_stack_builder_create_iterator_at_last(builder);
-    GPR_ASSERT(grpc_channel_stack_builder_move_prev(it));
     const bool retval = grpc_channel_stack_builder_add_filter_before(
         it, filter, nullptr, nullptr);
     grpc_channel_stack_builder_iterator_destroy(it);
@@ -326,15 +325,15 @@ static bool maybe_add_filter(grpc_channel_stack_builder* builder, void* arg) {
 
 static void init_plugin(void) {
   gpr_mu_init(&g_mu);
-  grpc_channel_init_register_stage(GRPC_CLIENT_CHANNEL, INT_MAX,
-                                   maybe_add_filter,
-                                   (void*)&test_client_filter);
-  grpc_channel_init_register_stage(GRPC_CLIENT_DIRECT_CHANNEL, INT_MAX,
-                                   maybe_add_filter,
-                                   (void*)&test_client_filter);
-  grpc_channel_init_register_stage(GRPC_SERVER_CHANNEL, INT_MAX,
-                                   maybe_add_filter,
-                                   (void*)&test_server_filter);
+  grpc_channel_init_register_stage(
+      GRPC_CLIENT_CHANNEL, GRPC_CHANNEL_INIT_PRIORITY_MAX, maybe_add_filter,
+      (void*)&test_client_filter);
+  grpc_channel_init_register_stage(
+      GRPC_CLIENT_DIRECT_CHANNEL, GRPC_CHANNEL_INIT_PRIORITY_MAX,
+      maybe_add_filter, (void*)&test_client_filter);
+  grpc_channel_init_register_stage(
+      GRPC_SERVER_CHANNEL, GRPC_CHANNEL_INIT_PRIORITY_MAX, maybe_add_filter,
+      (void*)&test_server_filter);
 }
 
 static void destroy_plugin(void) { gpr_mu_destroy(&g_mu); }

test/core/end2end/tests/filter_status_code.cc

@@ -333,7 +333,6 @@ static bool maybe_add_filter(grpc_channel_stack_builder* builder, void* arg) {
     // So we add it right before the last one.
     grpc_channel_stack_builder_iterator* it =
         grpc_channel_stack_builder_create_iterator_at_last(builder);
-    GPR_ASSERT(grpc_channel_stack_builder_move_prev(it));
     const bool retval = grpc_channel_stack_builder_add_filter_before(
         it, filter, nullptr, nullptr);
     grpc_channel_stack_builder_iterator_destroy(it);
@@ -350,15 +349,15 @@ static void init_plugin(void) {
   g_client_code_recv = false;
   g_server_code_recv = false;
 
-  grpc_channel_init_register_stage(GRPC_CLIENT_CHANNEL, INT_MAX,
-                                   maybe_add_filter,
-                                   (void*)&test_client_filter);
-  grpc_channel_init_register_stage(GRPC_CLIENT_DIRECT_CHANNEL, INT_MAX,
-                                   maybe_add_filter,
-                                   (void*)&test_client_filter);
-  grpc_channel_init_register_stage(GRPC_SERVER_CHANNEL, INT_MAX,
-                                   maybe_add_filter,
-                                   (void*)&test_server_filter);
+  grpc_channel_init_register_stage(
+      GRPC_CLIENT_CHANNEL, GRPC_CHANNEL_INIT_PRIORITY_MAX, maybe_add_filter,
+      (void*)&test_client_filter);
+  grpc_channel_init_register_stage(
+      GRPC_CLIENT_DIRECT_CHANNEL, GRPC_CHANNEL_INIT_PRIORITY_MAX,
+      maybe_add_filter, (void*)&test_client_filter);
+  grpc_channel_init_register_stage(
+      GRPC_SERVER_CHANNEL, GRPC_CHANNEL_INIT_PRIORITY_MAX, maybe_add_filter,
+      (void*)&test_server_filter);
 }
 
 static void destroy_plugin(void) {

test/cpp/common/channel_filter_test.cc

@@ -50,7 +50,8 @@ class MyCallData : public CallData {
 // C-core, we don't accidentally break the C++ filter API.
 TEST(ChannelFilterTest, RegisterChannelFilter) {
   grpc::RegisterChannelFilter<MyChannelData, MyCallData>(
-      "myfilter", GRPC_CLIENT_CHANNEL, INT_MAX, nullptr);
+      "myfilter", GRPC_CLIENT_CHANNEL, GRPC_CHANNEL_INIT_PRIORITY_LOW, true,
+      nullptr);
 }
 
 // TODO(roth): When we have time, add tests for all methods of the

test/cpp/end2end/filter_end2end_test.cc

@@ -323,7 +323,8 @@ TEST_F(FilterEnd2endTest, SimpleBidiStreaming) {
 
 void RegisterFilter() {
   grpc::RegisterChannelFilter<ChannelDataImpl, CallDataImpl>(
-      "test-filter", GRPC_SERVER_CHANNEL, INT_MAX, nullptr);
+      "test-filter", GRPC_SERVER_CHANNEL, GRPC_CHANNEL_INIT_PRIORITY_LOW, true,
+      nullptr);
 }
 
 }  // namespace